Apparatus for placing cover sheets on stacks of different heights

ABSTRACT

A conveyor has a substantially horizontal upper run on which stacks of different heights are continuously advanceable. A pusher member is mounted above the upper run and movable in a straight line between a rest position in which it is spaced farther upwardly from, and an operated position in which it is closer to the upper run. A drive moves the pusher member between the positions thereof, and a feed arrangement is located laterally of the straight line intermediate the aforementioned positions and serves to engage a cover sheet at a margin thereof for feeding the cover sheet into the path of movement of the pusher member. An actuating arrangement actuates the drive for the pusher member in such a manner that the pusher member will push a cover sheet into contact with the respective stack when the latter is in alignment with the straight line.

United States Patent [191 1111 3,923,145

Muller 1 Dec. 2, 1975 [54] APPARATUS FOR PLACING COVER 3,404,880 10/1968 Porter ct a1 270/58 SHEETS 0 STACKS OF DIFFERENT 3,456,8l5 7/1969 Carrels 2l4/6 G HEIGHTS Inventor: Hans Muller, Zofingen, Switzerland Grapha-Holding AG, Hergiswil, Switzerland Filed: Nov. 14, 1973 Appl. No.: 415,804

Assignee:

Foreign Application Priority Data Nov. 17, 1972 Switzerland. 16831/72 References Cited UNITED STATES PATENTS 3/1962 Harrison 53/74 l/l967 Jensen et al 214/1 BS Primary ExaminerEvon C. Blunk Assistant ExaminerJoseph E. Valenza Attorney, Agent, or FirmMichael S. Striker [57] ABSTRACT A conveyor has a substantially horizontal upper run on which stacks of different heights are continuously advanceable. A pusher member is mounted above the upper run and movable in a straight line between a rest position in which it is spaced farther upwardly from, and an operated position in which it is closer to the upper run. A drive moves the pusher member between the positions thereof, and a feed arrangement is located laterally of the straight line intermediate the aforementioned positions and serves to engage a cover sheet at a margin thereof for feeding the cover sheet into the path of movement of the pusher member. An actuating arrangement actuates the drive for the pusher member in such a manner that the pusher member will push a cover sheet into contact with the respective stack when the latter is in alignment with the straight line.

8 Claims, 4 Drawing Figures US. Patent 1560.2, 1975 Sheet 1 of? I U 3,923,145-

FIGJ

U.S. Patent Dec. 2; 1975 Shet 2 of3 3,923,145

APPARATUS FOR PLACING COVER SHEETS ON STACKS OF DIFFERENT HEIGHTS BACKGROUND OF THE INVENTION The present invention relates generally to an apparatus for placing cover sheets on stacks, for instance stacks of paper or the like, and more particularly to such an apparatus which places cover sheets on contin- 1 stance, are counted by machine and formed into stacks.

of different height, depending upon how many magazines or newspapers are to be in each stack which is then to be packed for shipment. These stacks are then supplied to the packaging equipment. Of course, the newspapers or magazines must be protected against damage, for which purpose cover sheets are placed onto the respective stacks prior to the packaging of the latter. In many instances, the address to which the stack is to be shipped is printed or otherwise provided on the cover sheet itself.

For economic reasons it is not practical to apply the cover sheet manually, and equipment has therefore been proposed for carrying out the application of the cover sheet. This equipment, however, can be used only if all consecutive stacks are of identical height. Unfortunately, this a condition which in many instances does notobtain, since for example one newsdealer will receive a greater number of a given newspaper or magazine than another. If, however, the consecutive stacks being supplied to the packaging equipment are of different heights, the prior-art cover sheet applying equipment could not be used and the application of the cover sheets had to be carried out by hand.

SUMMARY OF THE INVENTION Accordingly, it is a general object of the invention to overcome the disadvantages of the prior art.

More particularly, it is an object of the present invention to apply cover sheets to sequentially arriving stacks, for instance of paper or the like, which are of different heights.

An additional object of the invention is to provide such an apparatus which assures reliable application of the cover sheets, whether the stacks are of different heights or of identical heights.

In keeping with the above objects, and with others which will become apparent hereafter, one feature of the invention recites, in an apparatus for placing cover sheets on stacks of different heights, in a combination which comprises a conveyor having a substantially hor-' izontal upper run on which stacks of different heights are continuously advanceable. A pusher member is mounted above the upper run and movable in a straight line between a rest position farther from, and an operated position closer to the upper run. Drive means is provided for moving the pusher member between its positions. Feed means is arranged laterally of the straight line intermediate the positions of the pusher member, for engaging a cover sheet at a margin thereof, and for feeding this cover sheet into the path of movement of the pusher member. Actuating means is provided for actuating the drive means in such a manner that th e pusher member pushesthe cover sheet into 2 contact with a respective stack when the latter is in alignment with the straight line.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a somewhat diagrammatic side view of the arrangement according to the present invention;

FIG. 2 is a view as seen in the direction of the arrow II in FIG. 1;

FIG. 3 is a fragmentary enlarged sectional view showing a detail of FIG. 2; and

FIG. 4 is a diagram explaining the operation of the embodiment in FIGS. 1-3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawing, and firstly to the embodiment as structurally shown in FIGS. 1-3, it will be seen that reference numeral 1 identifies a support on which there is mounted a conveyor belt 3 which can be driven by a motor 2. The conveyor belt has a substantially horizontal upper run which supports consecutive stacks S1, S2 and S3 which may be of paper or the like. These stacks are advanced at the conveying speed V1 of the conveyor belt 3, from right to left in FIG. 1.

Arranged laterally of the support 1 is a further support 4 which carries a magazine 5 which accommodates a stack 6 of cover sheets, each of which is to be placed upon one of the stacks S1, S2, etc. Reference numeral 7 identifies an arrangement for singly withdrawing cover sheets 6 from the magazine 5 and sup plying them to a conveyor 8. A pair of counter-pressure rollers 10 are freely turnably mounted in two laterally arranged guide rails 6 and cooperate with the conveyor belt 8. The device 7 need not be specifically described because it is known in the art; such a device is, for instance, available under the tradename MultiFeed 250 from Multimatic AG, Kuessnacht, Switzerland.

A pair of rails 11 are located laterally of the conveyor 8 and below the rails 9; they have upper glide surfaces which are planar with the upper run of the conveyor 8. The latter pushes the cover sheets 6 along the rails 11 and against an abutment 12. When a cover sheet 6 is in engagement with the abutment 12, it is arranged in axial alignment with the path of movement 13 of a pusher member 14, which path is a straight line extending normal to the upper run of the conveyor 3. The side edges of the sheet 6 are supported on the rails 11.

The pusher member 14 is shown in FIG. 1 in a rest position. It must, of course, be moved downwardly together with a cover sheet 6 to an operating position, and must then be retracted to rest position. For this purpose, the member 14 is mounted on an arm 15 which is connected with the piston rod 16 of a pneumatic cylinder unit 17 which is rigidly connected with an element 18 that is mounted on the frame 4. A twoway valve 19 operates the cylinder 17. When the first output 19' of the valve 19 supplies pneumatic fluid to the cylinder 17, then the pusher member 14 is lowered from its upper rest position into a lower operating position. When the pusher member 14 is subsequently to be raised back to the rest position, the valve 19 must be reversed in its operation, as will be described later so that pneumatic fluid is supplied to the cylinder 17 from the output 19 of the valve 19.

The details of the pusher member are shown most clearly in FIG. 3. The member 14 will be seen to have a cylindrical upwardly closed sleeve 20, the interior of which is connected with a non-illustrated source of suction by means of a conduit 21. Two plates 23 which are provided with bores 22 are arranged in the interior of the sleeve and positioned in parallelism. Air which enters from below into the sleeve is drawn through the bores 22 into the conduit 21.

A pneumatic cylinder 24 is mounted between the plates 23 and has a piston rod 25 which extends through a bore 26 in the lowermost plate 23 and into a cylinder 27 which is fixedly connected with the plate 23 and has a cylindrical bore 28 serving as a guide for the piston rod 25. The latter is in its inner end position, as shown in FIG. 3. When it is in its outer end position, shown in broken lines in FIG. 3, it projects past the cylinder 27. When a cover sheet 6 overlies the opening 29 of the sleeve 20, and the piston rod 25 is in its inner end position, then a suction exists in the space 30 which draws the cover sheet against the member 14 and holds it in place. When the piston rod 25 is lowered, then the suction in space 30 breaks down, and at the same time the cover sheet 6 is pushed away from the member 14 by the piston rod 25.

I have pointed out before that the cylinder 17 is controlled by a two-way valve 19. Similarly, a two-way valve 31 controls the cylinder 24. When the output 31 of the valve 31 supplies pneumatic fluid to the cylinder 24, then the piston rod 25 is raised and the air which can enter into the space 30 can draw a cover sheet in place against the opening 29. When fluid is supplied via the output 31 of the valve 31, the piston rod 25 is lowered and a cover sheet 6 which is in place on the member 14 is pushed away from the latter.

The operations of the valve 19 are controlled by a first sensing arrangement 32 having a photoelectric cell 33 and an associated mirror 34 which is shown in FIG. 1, and a second sensing arrangement 35 which is shown in FIG. 2 and uses a photoelectric cell 36 and an associated mirror 37. If the beam of the first arrangement 32 is interrupted by one of the stacks S1, S2, S3, then the photoelectric cell 33 will upon subsequent termination of this interruption supply a signal to the valve 19 which causes the latter to operate in such a manner that it supplies pneumatic fluid via its output 19" to the cylinder l7, lowering the member 14. At this time, a flipflop element 38 controls the valve 31 in such a manner that the latter supplies pneumatic fluid to the cylinder 24 via its output 31', causing the piston rod 25 to be retained in its inner end position. During further descent of the member 14 the beam of the sensor 35 moves into the region of the stack which at any given time is below the member 14, and is thereby interrupted. This produces a signal in the photoelectric cell 36 which signal is supplied to the valve 19 on the one hand, and via the flip-flop element 38 to the valve 31 on the other hand. This causes the operation of both valves to be reversed, so that the output 19' of the valve 19 now supplies fluid t the cylinder 17 which causes the member 14 to be raised. At the same time, the output 31 of the valve 31 supplies fluid to the cylinder 24 which moves the piston rod 25 to its outer end position, that is to a position in which it pushes the cover sheet 6 which heretofore has been attracted to the member 14, away from the latter.

During the upward movement of the member 14, the beam of the sensor 35 again impinges upon the mirror 37. As soon as the member 14 approaches its upper end position, the beam of the sensor 35 is again interrupted and the signal supplied by the cell 36 is terminated. This causes the flip-flop element 38 to activate the valve 31 in a sensecausing it to supply the cylinder 24 with fluid again via the output 31, so that the piston rod 25 is retracted to its inner end position. At the same time, the element 38 supplies a signal to the device 7, causing the same to withdraw another cover sheet 6 from the magazine 5 and to supply it to the conveyor 8.

The member 4 and the conveyor 3 move at constant speeds V2 and V1, respectively. To assure that the member 14 with the respective cover sheet 6 will always contact the respective stacks S1, S2 or S3 at the time at which they are in alignment with the path 13, independent of the height H of the respective stack, the movement of the member 14 must be initiated sooner or later in dependence upon the height H of the respective stack. For this purpose, the beam of the sensor 32 is inclined with respect to the conveyor 3 so as to include with the same an acute angle a.

The diagram in FIG. 4 shows three stacks of differential heights H1, H2 and H3 at the moment at which the beam of the sensor 32 is free. The smaller the heights H1, H2 and H3, the greater will be the corresponding distances a1, a2 and a3 from the middle of the stack to the path 13. correspondingly, the movement of the member 14 will be started. Given a fixed relationship V1/V2 of the speeds of the conveyor 3 and the member 4 on the one hand, and given a maximum stroke W of the member 14 on the other hand, the beam of the sensor 32 and the angle a are to be so arranged that the distance a of the center of the stack from the path 13 satisfies the requirement wherein W; is the difference between the maximum stroke W and the stack height H.

It is possible, according to a further embodiment of the invention, to measure the height of the stacks S1, S2 and S3 at a predetermined distance a from the path 13, and to accelerate or retard the speed of movement of the member 14 and/or the belt 3 in dependence upon the respectively measured stack height.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of contructions differing from the type described above.

While the invention has been illustrated and described asembodied in an apparatus for applying cover sheets to stacks of different heights, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

1. In an apparatus for placing cover sheets on stacks of different heights, a combination comprising a conveyor having a substantially horizontal upper run on which stacks of significantly different heights are continuously advanceable at a constant rate of speed; a pusher member mounted above said upper run and movable at a constant rate of speed in a straight line between a rest position farther from, and an operated position closer to said upper run; drive means for movingsaid pusher member between said positions; feed means laterally of said straight line intermediate said positions for engaging a cover sheet at a margin thereof, and for feeding said cover sheet into the path of movement of said pusher member; retaining means for engaging and retaining a respective cover sheet on said pusher member as the same moves towards said operated position; and actuating means for actuating said drive means in response to the approach of a stack towards said pusher member, including sensing means which senses the upper trailing edge of the approaching stack, so that in response to said sensing of said upper trailing edge of the approaching stack said pusher member is actuated and pushes a retained cover sheet into contact with the respective stack when the latter is in precise alignment with said straight line.

2. A combination as defined in claim 1, wherein said sensing means includes a light source and a photoelectric cell which are arranged so that a light beam between them includes an acute angle with said upper run.

3. A combination as defined in claim 1, wherein said drive means comprise a pneumatic cylinder and piston unit, a reversing valve controlling fluid flow to and from said unit, and a detector which detects contact of said piston member with a stack and in response reverses said valve.

4. A combination as defined in claim 1, wherein said piston member comprises a sleeve having a closed upper and an open lower end, and a separating element accommodated in said sleeve and operative for separating a retained cover sheet therefrom when said pusher member is in contact with a stack.

5. A combination as defined in claim 4, wherein said separating element has a cylinder and a pneumatic piston reciprocable in said cylinder between a position in which it is withdrawn into the same and a position in which said piston axially projects from said open end of said sleeve.

6. A combination as defined in claim 5; said retaining means comprising openings in said sleeve symmetrically spaced about the axis of the same, and connecting means connecting the interior of said sleeve with a source of suction.

7. A combination as defined in claim 1; and further comprising guide rails for said feed means, said guide rails being arranged symmetrically relative to said straight line.

8. A method of placing cover sheets onto stacks of different heights, comprising the steps of sequentially advancing stacks of significantly different heights at a constant rate of speed in a path towards a working station at which a pusher member is vertically movable in a straight line and at a constant rate of speed toward and away from the path in which the stacks advance; sensing the upper trailing edge of a stack approaching the working station; initiating movement of the pusher member towards said path in response to such sensing of said upper trailing edge of the approaching stack, at which time the approaching stack is spaced from said straight line by a distance whose magnitude is proportional to the height of the stack, so that the pusher member is actuated and will engage the top of the approaching stack when the latter is in precise alignment with said straight line; and feeding a cover sheet to be placed onto said top into the line of movement of said pusher member for engagement by the same and deposition onto said top. 

1. In an apparatus for placing cover sheets on stacks of different heights, a combination comprising a conveyor having a substantially horizontal upper run on which stacks of significantly different heights are continuously advanceable at a constant rate of speed; a pusher member mounted above said upper run and movable at a constant rate of speed in a straight line between a rest position farther from, and an operated position closer to said upper run; drive means for moving said pusher member bEtween said positions; feed means laterally of said straight line intermediate said positions for engaging a cover sheet at a margin thereof, and for feeding said cover sheet into the path of movement of said pusher member; retaining means for engaging and retaining a respective cover sheet on said pusher member as the same moves towards said operated position; and actuating means for actuating said drive means in response to the approach of a stack towards said pusher member, including sensing means which senses the upper trailing edge of the approaching stack, so that in response to said sensing of said upper trailing edge of the approaching stack said pusher member is actuated and pushes a retained cover sheet into contact with the respective stack when the latter is in precise alignment with said straight line.
 2. A combination as defined in claim 1, wherein said sensing means includes a light source and a photoelectric cell which are arranged so that a light beam between them includes an acute angle with said upper run.
 3. A combination as defined in claim 1, wherein said drive means comprise a pneumatic cylinder and piston unit, a reversing valve controlling fluid flow to and from said unit, and a detector which detects contact of said piston member with a stack and in response reverses said valve.
 4. A combination as defined in claim 1, wherein said piston member comprises a sleeve having a closed upper and an open lower end, and a separating element accommodated in said sleeve and operative for separating a retained cover sheet therefrom when said pusher member is in contact with a stack.
 5. A combination as defined in claim 4, wherein said separating element has a cylinder and a pneumatic piston reciprocable in said cylinder between a position in which it is withdrawn into the same and a position in which said piston axially projects from said open end of said sleeve.
 6. A combination as defined in claim 5; said retaining means comprising openings in said sleeve symmetrically spaced about the axis of the same, and connecting means connecting the interior of said sleeve with a source of suction.
 7. A combination as defined in claim 1; and further comprising guide rails for said feed means, said guide rails being arranged symmetrically relative to said straight line.
 8. A method of placing cover sheets onto stacks of different heights, comprising the steps of sequentially advancing stacks of significantly different heights at a constant rate of speed in a path towards a working station at which a pusher member is vertically movable in a straight line and at a constant rate of speed toward and away from the path in which the stacks advance; sensing the upper trailing edge of a stack approaching the working station; initiating movement of the pusher member towards said path in response to such sensing of said upper trailing edge of the approaching stack, at which time the approaching stack is spaced from said straight line by a distance whose magnitude is proportional to the height of the stack, so that the pusher member is actuated and will engage the top of the approaching stack when the latter is in precise alignment with said straight line; and feeding a cover sheet to be placed onto said top into the line of movement of said pusher member for engagement by the same and deposition onto said top. 